Tweedia is a tropical twining vine and subshrub native to Brazil and Uruguay that grows 24, 36 inches tall and wide, prized for its striking sky blue flowers that bloom from summer through fall. In hardiness zones 10, 11, it thrives as a perennial shrub, but gardeners in cooler climates easily grow it as an annual from seed started indoors. The five-petaled flowers appear in delicate clusters and are followed by narrow, ornamental seedpods, while the velvety ovate leaves and milky sap when cut reveal its membership in the dogbane and milkweed family. Its moderate care needs and tolerance for a wide range of soils make it an accessible choice for gardeners seeking something unexpected.
Partial Sun
Moderate
10-11
36in H x 36in W
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Moderate
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The luminous sky blue flowers that emerge from summer into fall are reason enough to grow this plant, but tweedia rewards you with two seasons of visual interest: the blooms themselves and the equally showy narrow seedpods that follow. It's surprisingly tough, tolerating poor soils and thriving in locations most gardeners might write off, though it does appreciate afternoon shade in hot climates and protection from wind. The velvety foliage and tropical lineage give it an exotic presence that belies how easy it actually is to grow from seed.
Tweedia is grown as an ornamental for its showy flowers and seedpods, primarily in containers or garden beds where its twining stems and tropical appearance add visual drama. In zones 10, 11, it serves as a perennial shrub for mixed borders and tropical-styled gardens. In cooler climates, it's cultivated as an annual, started from seed indoors and transplanted after frost danger passes.
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Start seeds indoors 6, 8 weeks before your last frost date. Once seedlings emerge, maintain warm growing conditions until they're ready to transplant outdoors after frost danger has passed.
Harden off seedlings gradually over 7, 10 days before transplanting outdoors after the last frost date. Space plants 24, 36 inches apart. In zones 10, 11, you can direct sow after soil has warmed, though starting indoors gives you a head start on blooming.
Pinch stem tips in spring to encourage bushiness and a more compact, branching growth habit. Beyond this, tweedia requires minimal pruning; simply remove any dead or damaged stems as needed. In zones 10, 11 where it overwinters as a perennial, you can cut it back in late winter to rejuvenate growth.
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“Tweedia hails from the subtropical regions of Brazil and Uruguay, where it evolved as a twining subshrub adapted to warm climates and tropical conditions. Its journey to northern gardens began through seed catalogs and botanical institutions, where it was recognized as a plant that could thrive as an annual in cooler zones when started indoors before the last frost. The plant's milky sap and distinctive seedpods made it botanically interesting to gardeners and plant collectors, ensuring its place in cultivation despite its tropical origins.”